A day after President Bush got what he called a “thumping” at the polls, the president reached across the political divide with a promise to work with Democrats, and the new House leadership returned the favor. But the traditional post-election comity belied inevitable confrontations over any number of hard issues, none more difficult than the course of the war in Iraq.

Almost 6 in 10 voters said in exit polls that they disapproved of the war, and Bush immediately made it plain that he got the message,
offering up Defense Secretary Donald Rumsfeld’s head to victorious Democrats
. That doesn’t mean, however, that he intends to capitulate to their demands for a dramatic change of strategy in Iraq, raising the prospect of two years of tense battles over war policy.

Several times at a news conference Wednesday, Bush declined the opportunity to declare that the nomination of former CIA Director Robert Gates to replace Rumsfeld meant he was taking a new course in Iraq. If confirmed by the Senate, he said, Gates would bring “a fresh perspective” and “great managerial experience” to the Pentagon, but the goal would remain the same.

“It’s very important that the people understand the consequences of failure,” Bush said. “And I have vowed to the country that we’re not going to fail. We’re not going to leave before the job is done.”

That isn’t likely to sit well with newly emboldened Democratic congressional leaders.

“Unfortunately, the course in Iraq cannot be changed solely by changing personnel,” Sen. Harry Reid, D-Nev., who would become majority leader if Democrat Jim Webb’s victory in Virginia survives a possible recount and his party takes over the Senate, said in a statement. “We also need a change in policy.”

Likewise, Sen. Joe Biden, D-Del., who would become chairman of the Foreign Relations Committee, said in a statement: “Regardless of Vice President Cheney’s ‘full steam ahead’ bravado, it is time for a radical change in course in Iraq.”

The first dramatic clash could come very soon. In an interview with MSNBC-TV on Wednesday, Biden said that as soon as the 110th Congress opened in January, he would convene hearings modeled on the historic examination of the Vietnam War conducted by Sen. William Fulbright, D-Ark., in 1971.

Notwithstanding the boldness of their challenge, the Democrats have to navigate a delicate path on Iraq, because while they called for major change during the campaign, very few —especially the party’s national figures, notably Sen. Hillary Rodham Clinton of New York — said what they would do instead.

The otherwise conciliatory-sounding Bush seized on that Wednesday. He challenged Democrats, in essence, to put up or shut up, saying, “The Democrats are going to have to make up their mind about how they’re going to conduct their affairs.”

Here comes Nancy
While Iraq is first on the list, there are
many other land mines for Bush
, whose only defense against a Democratic agenda could be a veto pen he has wielded but once during his six years in office.

House Democratic leader Nancy Pelosi, a liberal San Franciscan who is expected to be elected the nation’s first female speaker in January, has promised to take on the president right out of the starting gate with an ambitious “First Hundred Hours” program to overhaul Washington.

The plan includes promises to reform lobbying and enact the recommendations of the bipartisan 9/11 commission, but it also includes several ideas that Bush has resisted: raising the minimum wage to $7.25 an hour, cutting the interest rate on student loans in half, streamlining Medicare’s prescription drug program and expanding federal funding for stem cell research.

More troubling for the White House is that with control of the House, Democrats will now be in control of the committees with oversight of its operations, a function they accused Republican chairmen of abdicating. Those committees will be led by some of the most senior Democrats hailing from the party’s liberal wing, and they will have subpoena power.

For example, John Conyers of Michigan, who is in line to head the Judiciary Committee, has said he would likely investigate a number of potentially embarrassing questions, such as the legality of the USA Patriot Act and Bush’s domestic surveillance act. And he has also said he might well call hearings on whether to impeach the president, although Pelosi has said she wouldn’t allow a vote.

Conyers’ Michigan colleague John Dingell, a fierce watchdog of energy issues, is set to head the Energy and Commerce Committee, where he could seek to haul in participants in Vice President Dick Cheney’s confidential energy task force. The Government Reform Committee will likely be headed by Henry Waxman of California, who keeps a public record of misleading statements by Bush officials.

As Rep. Ike Skelton of Missouri, chairman-to-be of the Armed Services Committee, put it, the watchword in the new Congress will be: “Oversight, oversight, oversight.”

Here (don’t) come the judges
Republicans would dearly love to get one more conservative on the Supreme Court, but that would be much tougher if the Democrats’ Senate victory is confirmed.

Now Bush could be squeezed by conservatives from the right and liberals from the left, and in a Demicratic Senate, those liberals would control the Judiciary Committee. Patrick Leahy of Vermont would be chairman; next in seniority on the Democratic side are Edward Kennedy of Massachusetts and Biden.

Who’s in charge?
During his first six years, Bush relied heavily on a united band of Republican leaders to force through his initiatives with little input from Democrats. If he hopes to lean on them in the new, divided government, he may have to ride out their growing pains.

Republicans will enter the 110th Congress with virtually all new leaders. House Speaker Dennis Hastert of Illinois
chose not to stay on
as leader of the Republican minority, and Senate Republican leader Bill Frist is retiring. And who will replace them isn’t yet clear.

Hastert’s deputy, John Boehner, will try for the leadership, but he faces challenges from his own deputy, Roy Blunt of Missouri, and from Mike Pence of Indiana.

In the Senate
, Mitch McConnell of Kentucky is almost certain to succeed Frist. McConnell is a fierce partisan fighter who has shown little stomach during his four Senate terms for the compromise of leadership, which could lead to more deadlock.

By contrast, Pelosi and Reid have been in place for several years and are ready to push the buttons of power as soon as they take over. The question for Bush is how much progress they can make while the Republicans sort out their leadership issues and then bring those new leaders up to speed.

Bush’s hot-and-cold relationship with Sen. John McCain, R-Ariz., is permanently buried in the freezer because McCain wants to be president and recognizes that tying himself too closely to Bush could be fatal. That will mean Bush can no longer rely on McCain to mediate his disputes with moderate Republicans, as he has occasionally done in the past.

As soon as the scope of the Republican defeat became apparent Tuesday night, McCain began separating himself from Bush, telling NBC News’ Brian Williams that Republicans had lost their way and that Republicans’ frustration “reflects on the president, as well.”

Alluding to Bush’s sometimes heavy-handed quashing of dissent, McCain lamented that “many in our base believed we valued power over principle.”

Similarly, Bush is losing an occasional ally of a most curious stripe: Clinton, who entered the Senate with a goal of establishing herself as a serious legislator who could, when necessary, work across party lines. That became an issue during her re-election campaign, as critics complained that she was too supportive of Bush’s Iraq policies.

As chairman of the Senate Foreign Relations Committee, Biden would have a prominent platform from which to pummel the president.

In addition to Armed Services, Sen. Evan Bayh, D-Ind., also serves on the Intelligence Committee, another platform for vocal opposition.

Sen. Russ Feingold, D-Wis., has never been shy about blasting the White House. If he runs, he would have every reason to ratchet up the pressure.

And like McCain, other would-be Republican presidents will relish the chance to increase their national profile:

Sen. Sam Brownback of Kansas has suggested that, if anything, Bush is not conservative enough. He helped torpedo the nomination of Harriet Miers to the Supreme Court from the right, for example.

If he runs, Sen. Chuck Hagel of Nebraska would have great incentive to try to step up beyond his image as McCain Lite. Opposition to Bush has played well for him — he raised early questions about the war in Iraq, and he voted against Bush’s prescription drug plan.

It all adds up to a headache for the president. Democrats have been frozen out for six years, and as Clinton said, “We have some unfinished business.”